Rollers

ABSTRACT

A resilient roller consisting of a cylindrical core member and a thin sleeve surrounding the core and spaced therefrom by resilient seals, the space between the core and the sleeve being filled with a liquid.

United States Patent Clarke et al. 1 Oct. 24, 1972 [54] ROLLERS I1,702,140 I 2/ 1929 Topham ..118/234 [72] Inventors: Kenneth Clarke,Knebworth; Ronald i Bevan, Welwyn, both of England e c 73] Assignee:Imperial Chemical Industries FOREIGN PATENTS OR APPLICATlONS Limited,London, England 1,076,499 7/1967 Great Britain ..29/ 1 10 1,416,9509/196 5 France ..29/110 [22] 1970 1,460,172 2/1969 Germany [21] Appl.No.: 98,652 127,970 7/ 1900 Germany 128,143 7/ 1900 Germany 83 2 1964 d52 us. C1. ..29/113 R 700 9 1 a l Cl- ..BZlb im yv a i L G. achl [58]Field of Search ..29/113, 110; 38/50, 49, Attorney cushman, Darby &Cushman R f C d [57] ABS I RACT 6 t [5 1 e erences l e A resilientroller consisting of a cylindrical core UNITED STATES PATENTS member anda thin sleeve surrounding the core and V spaced therefrom by resilientseals, the space between et a1 29/1 R the core and t ee e a 3,640,2182/1972 AlllSOH ....29/113 R 3,543,366 12/ 1970 Collet ..29/113 R 9Claims, 5 Drawing Figures Al IXAA I lrr PATENTEH ET 24 I97? 3. 699,62 1SHEET 1 [IF 4 Invenlor: F 2 Flam fr (2/76/65 M a @f A tlorneys ROLLERSThis invention relates to rollers and in particular to a roller systemthat may be used to apply uniform pressure to a work-piece.

In many processes a work-piece has to be passed between a pair ofrollers for one reason or another. Depending on the nature of theprocess, such rollers have heretofore been constructed from a variety ofmaterials including metals and rubber. Often it is desired that therollers exert a uniform pressure on the work-piece and in such casesrollers made from a resilient material such as rubber have been used.However, such rollers are generally unsuitable for use at elevatedtemperatures and are also liable to uneven wear. Also they areunsuitable where it is desired that the resilient roller has a hardand/or high quality, e.g. polished surface.

In our Dutch Patent application 68,1666? we described resilient liquidfilled plates which were designed to overcome disadvantages, associatedwith rubber and other resilient materials in a pressing process. Inthese plates a cushion of liquid was trapped between two thin metalsheets joined to each other round their periphery. Adaptation of thisprinciple to a roller system would be highly desirable for use inprocesses wherein a work-piece has to be passed through rollers, forexample as in a continuous process.

However, the mere provision of a resilient thin metal tube filled with aliquid bearing against a rigid roller would not itself be satisfactorysince it would not be possible to apply any appreciable pressure to aworkpiece passed between the nip of such a roller system since theresilient roller would merely deform and lessen the effective pressure.

This difficulty may be overcome by supporting the opposite side of theresilient roller to the nip through which the work-piece passes byanother one or more further rigid rollers. Thus the resilient roller maybe mounted as a member of a roller train of at least three rollers sothat the resilient roller is mounted and supported between at least tworigid rollers at least one of which is biassed towards the axis of theresilient roller so as to apply pressure thereto.

In addition, some means has to be devised to seal the space enclosed bythe thin metal tube. If the ends of the tube are attached e.g. bywelding, to rigid end plates, the ends of the resilient roller will beappreciably more rigid than the middle portion of the roller with theresult that the deformation that could be permitted by such a resilientroller would vary over the length of the roller.

This latter problem can sometimes be overcome by making the resilientroller appreciably longer than the rigid rollers so that the ends of theresilient roller extend beyond the ends of the rigid rollers for adistance sufficient to accommodate the transition from the resilient midportion of the resilient roller to the rela tively rigid end portions ofthe resilient roller.

However, attaching the tube ends e.g. by welding to rigid end plates isan inherently impracticable method of sealing the space enclosed by thetube and problems such as differential thermal expansion arise. Suchseals are also not particularly robust and the seals often burst whenthe resilient roller is being used.

We have now devised a more practicable and more robust form of resilientroller construction that removes the necessity for the ends of the tubeof the resilient roller to be rigidly attached to rigid end plates. Whensuch a roller is used it is not always necessary for its ends to extendbeyond the ends of the rigid rollers.

Accordingly, we provide a resilient roller for use in a roller traincomprising a rigid cylindrical core member and a cylindrical thin metalsleeve surrounding said core and held spaced therefrom by resilientsealing members at either end of the sleeve, which sealing members alsoseal the space enclosed between the core and the sleeve, said spacebeing filled with a filling material that is liquid under the conditionsof use of said resilient roller.

The core member is preferably provided with flanges against which thesealing members may abut to prevent them being forced out of the sleevewhen pressure is applied thereto. Alternatively the: same object may beachieved by providing the core member with grooves in which the sealingmembers are located.

Any suitable sealing members may be used in the present invention.Examples of suitable members include O-rings, chevron rings and rubberrings that are attached rigidly to leaf springs. O-rings areparticularly cheap and convenient sealing members and the invention willhereinafter be described in terms of O-ring sealing members although itis to be understood that the invention is by no means limited toO-rings.

The O-rings, which are preferably made of rubber, permit flexing of thethin metal sleeve while providing an adequate support for the sleeve andalso a seal to contain the filling material within the space between thesleeve and the core member.

The invention is illustrated by the accompanying drawings, wherein:

FIG. 1 is a longitudinal section of a resilient roller in accordancewith the invention.

FIG. 2 is a diagrammatic end elevation of a roller train incorporating aresilient roller in accordance with the invention.

FIG. 3 is a side elevation of a roller train incorporating a resilientroller in accordance with the invention.

FIG. 4 is a section of the roller train shown in FIG. 3 along the lineIV IV.

FIG. 5 is a cross section along the line V V of FIG. 4.

The roller depicted in FIG. 1 consists of a cylindrical core member 1and a thin metal sleeve 2 held spaced from core member 1 by two rubberO-rings 3,4. The 0- rings also seal the space between core member 1 andsleeve 2.

O-ring 3 abuts against a flange 5 formed integrally with core member 1.Flange 5 has a diameter less than the inside diameter of the thin metalsleeve 2 and extends inside said sleeve 2. Adjacent to flange 5 is asecond flange 6 also formed integrally with core member 1. Flange 6 hasa diameter greater than the inside diameter of sleeve 2 but less thanthe outside diameter of sleeve 2. This flange 6 limits longitudinalmovement of sleeve 2. Typically the sleeve 2 may be made of stainlesssteel of thickness 0.75 mm.

The other end of core member 1 from flange 6 is threaded and carries asecond sleeve 7, which is shaped to correspond to flanges 5 and 6 oncore member 1, and thus provides an abutment for O-ring 4 and a limitfor longitudinal movement of sleeve 2. Sleeve 7 is held on the coremember 1 by a nut 8.

The space 9 between the sleeve 2 and core member 1 is filled with amaterial that is liquid under the intended conditions of use of theroller.

The material used for the O-rings should of course be inert to thematerial used to fill space 9.

As mentioned above the resilient roller may be used in a roller trainbetween two or more rigid cylindrical rollers.

Typically the resilient roller is mounted between three parallel rigidrollers with its longitudinal axis parallel to the axes of the rigidrollers, so that a workpiece to which it is desired to apply pressurecan pass between one or more of the three nips between the resilientroller and the rigid roller, said rigid rollers being mounted such that,in a section in the plane perpendicular to the longitudinal axes of therollers, the longitudinal axes of the rigid rollers lie at the comers ofa triangle, and, when the work-piece is in position, the center of theresilient roller lies within said triangle and the resilient rollercontacts the work-piece at each of the nips between the rigid rollersand the resilient roller through which the work-piece passes andcontacts the rigid rollers at any nip through which the work-piece doesnot pass, the resilient roller being of such diameter that it deformsslightly at each of the three places of contact thereby applyingpressure to the work-piece.

The work-piece can pass through one, two or all three of the nipsbetween the resilient rollers and the rigid rollers. Where it passesthrough only'one nip the resilient roller will contact the two otherrigid rollers themselves; where it passes through two of the nips, theresilient roller will only contact one rigid roller; while where thework-piece passes through all three nips, the resilient roller nowherecontacts the rigid rollers themselves.

A typical roller train is depicted in FIG. 2 wherein the three rigidrollers 1,2,13,14, are shown having their axes at the comers of triangleABC. The resilient roller 15 is mounted with its center, 0, insidetriangle ABC. It will be appreciated that if the center was outside thetriangle ABC, the support for the resilient roller given by the rigidrollers would generally be inadequate. The work-piece 16 passes betweenthe nip between rigid roller 12 and the resilient roller 15. The radiusof resilient roller 15 is slightly greater than the radius of the circle17 (indicated by broken lines) which circle is then inscribed betweenrollers 13 and 14 and the work-piece 16. Resilient roller 15, thereforeis deformed at the places where it contacts the rigid rollers 13 and 14and the work-piece 16 so that pressure is applied to the work-piece 16.

One convenient way of mounting the rollers is to mount two of the rigidrollers in fixed positions and the third rigid roller in guides so thatit can be biassed, e.g. by means of springs or weights, towards thecenter of the resilient roller. The resilient roller, being supported bythe rigid rollers, needs no mountings to take lateral thrusts but shouldbe provided with thrust bearings to take longitudinal thrusts. Suchthrust bearings may conveniently take the form of an oilite washer or aplate of low friction material such as polytetrafiuoroethylene againstwhich the ends of the core of the resilient roller engages.

In a preferred form the two rigid rollers mounted in fixed positions arethe same size and the third roller,

which may also be the same size, is mounted such that in the planeperpendicular to theaxes, its longitudinal axis is at the apex of anisosceles triangle with the axis of the two other rigid rollers at thebase corners of the triangle. In some cases the resilient roller canalso be mounted in guides, both the resilient roller and the rigidroller at the apex of the triangle being capable of I movement in a lineperpendicular to the base of the triangle.

Where the resilient roller is mounted in guides, if the work-piece isthin, in comparison to the radius of the rollers, it is immaterialthrough which nip or nips the work-piece passes in such a system.However, if the work-piece is relatively thick, to avoid undue stressesat the mountings of the resilient roller the work-piece should passthrough the nip between the rigid roller at the apex of the triangle andthe resilient roller, or through both of the nips between the rigidrollers at the base comers of the triangle and the resilient roller, orthrough all three of the nips so as to provide a symmetrical system.

In a system where a thick work-piece is to be'passed through one of thenips between the rigid rollers at the base of the triangle and theresilient roller, then it may be desirable, to avoid such stresses, toreduce the radius of that rigid roller by an amount equal to thethickness of the work-piece. Such stresses do not arise if the resilientroller, is only provided with thrust bearings to take longitudinalthrusts. A suitable roller train system is shown in FIGS. 3 to 5.

In this system three rigid rollers 18,19,20 are mounted with theirlongitudinal axes parallel with the axes 21,22,23 at the corners of anisosceles triangle as shown in FIG. 3. Rollers l8 and 19 have the sameradius while roller 20 has a radius less than that of rollers 18 and 19by an amount equal to the thickness of the work-piece 24. The axis 21,i.e. that of roller 18, is at the apex of the isosceles triangle, whileaxes 22 and 23 are at the base corners of the triangle. Rollers 19 and20 are mounted. in fixed positions in a frame 25 whereas the mounting 26for roller 18 is movable in a slot 27 in a direction perpendicular tothe base of the triangle and can be adjusted by means of screws 28.

The resilient roller 29, which has a construction of the type depictedin FIG. 1 but with the O-rings located in grooves in the core member issupported by rollers 19 and 20 and is provided with thrust bearings 30in the form of pads of polytetrafluoroethylene fastened to frame 25 andagainst which pads the ends of the core of roller 29 bear.

As stated hereinbefore, it is not always necessary, for the ends or theresilient roller to extend beyond the ends of the rigid rollers toaccommodate the transition from the resilient portion of the resilientroller to the rigid end portions, since the whole length of the thinmetal sleeve is resilient. Indeed to prevent the thin metal sleeve fromswelling, which would reduce the effective pressure applied and possiblygive rise to bursting or leaking at the ends of the sleeve, we preferthat the rigid rollers are longer than the distance apart of the O-ringssupporting the thin metal sleeve.

In the system depicted in FIGS. 3 to 5, the rigid rollers 18,19,20 areshow to be of the same length as the thin metal sleeve 31 or resilientroller 29. Provided the flanged end portions of resilient roller 29(corresponding to portions 6 and 7 of the roller in FIG. 1) do not havea diameter greater than the circle inscribed between the rollers 18 and19 and work-piece 24 when the desired pressure is applied, the rigidrollers can extend over these flanged portions if desired. However,there is little advantage in so doing as the useful nip lengthis ofcourse limited by the length of the thin metal sleeve 31. Preferably thewidth of the work-piece 24 is the sameas or greater than the distancebetween the O-rings supporting the thin metal sleeve 31 so as to avoidpermanent distortion of the sleeve 31.

In a system of more than three rigid rollers, the resilient roller mustbe made larger in order to engage with all the rigid rollers. Increasingthe size of the resilient roller requires the use of thicker gauge metalfor the tube in order to contain the pressure developed in the fillingmaterial. In such a system of more than three rigid rollers it is to beunderstood that the center of the resilient roller, should lie withinthe polygon formed by the longitudinal axes of the rigid rollers in aplane perpendicular to those axes.

The resilient roller may be subjected to relatively high pressures,depending on the application envisaged, and so of course has to beconstructed to have adequate strength. For this reason, particularlywhere relatively high pressures are required, it is preferred to makethe tube of this resilient roller from a metal such as high tensilesteel (which may be made rust resistant if necessary), high tensilealloy steel or a spring steel so that the wall thickness can be kept ata sufficiently low value to provide adequate resiliency.

Preferred resilient roller diameters are in the range 3 to cm,preferably less' than 5 cm. The wall thicknesses are preferably in therange 0.03 to 0.3 preferably less than 0.1 cm and particularly 0.05 to0.08 cm. The thickness of the layer of the liquid filling material ispreferably within the range 0.01 to 0.35 cm, particularly within therange 0.025 to 0.08 cm. It is also preferable that the roller bepre-pressurized, i.e. filled with a filling material under pressure.

The material used to fill the resilient roller has to be one that isliquid or rubbery under the conditions of the rolling operation. It isnot necessary, however, that it is liquid at room temperature if therolling is performed at an elevated temperature and in some casestherefore the filling material may be material that is solid at roomtemperature but having a melting point below the rolling temperature.

The possibility of the use of a filling material that is 7 solid at roomtemperature permits the use of some metallic materials as the fillingmaterial, thereby enabling advantage to be taken of the superior thermalconductivity of metals over non-metallic filling materials such as oilsand waxes where heat has to be conducted to the work-piece through thefilling material.

Where a filling material that is solid at room temperature is used, itis preferred, however, that the melting point of the filling material issubstantially lower than the rolling temperatures so that is ensuredthat all the filling material is liquid at the rolling temperature.

Since there is little advantage in the use of a higher melting solid,the filling material should have a melting point below 120C preferablybelow 100C.

Solids that can be used as filling materials in appropriate casesinclude organic compounds such as bismuth, lead, tin and/or cadmium.

The use of a filling material that is solid at room temperature hassomedisadvantages, particularly in relation to the operation of fillingthe rollers as it is generally necessary to fill the roller with thefilling material in the liquid state to ensure complete filling. Withthe use of a filling material that is solid at room temperature thismeans that the filling operation is complicated by the necessity of theuse of associated heating apparatus.

We therefore in general prefer to use a filling material that is liquidat room temperature, i.e. at about 18C.

Preferred filling materials include mineral oils, water, silicone oils,glycol and glycerol.

Glycerol, while having a reasonably good thermal conductivity has thedisadvantage that some steels and hence rollers made therefrom, catalyzethe decomposition and polymerization of glycerol.

This however, can be minimized by incorporating a suitable stabilizer inthe glycerol, for example, borax orl,l,3-tris-(3-t-butyl-4-hydroxy-6-methyl phenyl) butane.

Indeed, with any liquid, suitable stabilizers may be incorporated asnecessary, e.g. sodium nitrite may be added to water to inhibit rustformation when water is used to fill ferrous metal rollers.

Water is generally satisfactory and is the preferred filling materialas, for a liquid, it has a good thermal conductivity. However, becauseof its relatively low,

boiling point its use is generally limited to rolling temperatures belowabout 250C or else unnecessarily high pressures are required to maintainthe water in the liquid phase. For higher temperature work, glycol,glycerol or silicone or mineraloils may be used. However, becausesilicone and mineral oils have a poor thermal conductivity but areotherwise satisfactory, they are preferably only used as the fillingmaterial in rolling operations where no reliance is placed on thefilling material to conduct heat to or from the workpiece.

If desired, solid materials or other liquids may be mixed with thefilling material provided they remain uniformly dispersed in the fillingmaterial in order to improve its thermal conductivity properties.

The rigid rollers may be solid or may be nonresilient tubes suitablyprovided with means for mounting. While one object of the rollers of thepresent invention is to avoid the use of rubber faced rollers, in somecases it may be possible and advantageous, particularly where it isnecessary that the work-piece is gripped as it passes through the nip,to form the rigid roller or rollers from a resilient material such asrubber orprovide a rigid metal roller with a thin coating of a resilientmaterial such as rubber. If desired the resilient roller may be heatedor cooled for example by passing steam or water through a heating coilinserted in the filling material.

Examples of uses of the roller train are in the production of sheets,films and extruded foil of plastic'materials; coating sheet materialsuch as paper or plastic films with coatings of, for example, plasticmaterials; continuous lamination processes; and in the production ofbonded fabrics. When high quality plastics sheet is desired it is oftennecessary to use rollers having highly polished surfaces.

The roller trains of the present invention are of particular utility inthe production of bonded non-woven fabrics from synthetic filaments. Asan example,'the filaments, which may conveniently be bicomponentfilaments having, for example, a nylon 6.6 core and a nylon 6.6/nylon 6copolymer sheath, are extruded, optionally drawn and heat set, and abundle of filaments is passed to a pneumatic forwarding device. Theforwarding device is traversed above an advancing collecting surfacewhereby a web of filaments is manufactured. The web may then be bondedby passage through a nip consisting of a heated roller provided withprotrusions on its surface, and a solid backing roller, whereby the webis segmentally bonded. When using the roller train of the presentinvention, one of the solid rollers of the train is formed as a spikedroller by providing a number of protrusions having rectangular, squareor various cross-sections over all the surface of the roller atpredetermined intervals. This spiked roller, which can be heated to180C, can be pressed against the resilient roller under a load ofbetween 100-200 pounds per inch length of nip to give a high qualitysegmentally bonded fabric without causing any damage to the resilientroller.

We claim:

1. A resilient roller for use in a roller train consisting of a rigidcylindrical core member and a cylindrical thin metal sleeve surroundingsaid core and held spaced apart therefrom by resilient sealing membersat either end of the sleeve which is inwardly deformable over the wholeof its length, which sealing members also seal the space enclosedbetween the core and the sleeve, said sleeve being filled with a fillingmaterial that is a liquid under the conditions of use of said resilientroller.

2. A resilient roller as claimed in claim 1 in which the core member isprovided with means for limiting outward longitudinal displacement ofthe sealing members along the core member.

3. A resilient roller as claimed in claim 2 in which the means forlimiting outward longitudinal displacement of the sealing members alongthe core member are flanges situated at each end region of the coremember and which extend outwardly therefrom and against which thesealing members abut.

4. A resilient roller as claimed in claim 2 in which the means forlimiting outward longitudinal displacement of the sealing members aregrooves situated at each end region of the core in which the sealingmembers are seated.

5. A resilient roller as claimed in claim 1 in which the 1 metal sleevehas a diameter within the range 3 to 10 6. A resilient roller as claimedin claim 1 in which the metal sleeve has a thickness within the range0.03 to 7. A resilient roller as claimed in claim 1 in which the layerof filling material has a thickness within the range 0.01 to 0.35 cm.

8. A resilient roller as claimed in claim 1 in which the fillingmaterial is a liquid at room temperature.

9. A resilient roller as claimed in claim 8 in which the fillingmaterial is selected from the group consisting of mineral oil, siliconeoil, water, glycol and glycerol.

UNITED STATES PATENT OFFICE I CERTIFICATE. O E QQRRECTIQN Patent No. 3,99, 2 Dated October2 1,197?

Inventor(s) Kenneth Clarke and Ronald Bevari It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below;

In the heading, line 30 was omitted and should appear as follows: a

[30] Foreign Application Priority Data January 21, 1970 Great Britain2926/70 Signed and sealed this 2mm day of April 1973.

(SEAL) -Attest:

EDWARD M. FLETCHER, JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

1. A resilient roller for use in a roller train consisting of a rigidcylindrical core member and a cylindrical thin metal sleeve surroundingsaid core and held spaced apart therefrom by resilient sealing membersat either end of the sleeve which is inwardly deformable over the wholeof its length, which sealing members also seal the space enclosedbetween the core and the sleeve, said sleeve being filled with a fillingmaterial that is a liquid under the conditions of use of said resilientroller.
 2. A resilient roller as claimed in claim 1 in which the coremember is provided with means for limiting outward longitudinaldisplacement of the sealing members along the core member.
 3. Aresilient roller as claimed in claim 2 in which the means for limitingoutward longitudinal displacement of the sealing members along the coremember are flanges situated at each end region of the core member andwhich extend outwardly therefrom and against which the sealing membersabut.
 4. A resilient roller as claimed in claim 2 in which the means forlimiting outward longitudinal displacement of the sealing members arEgrooves situated at each end region of the core in which the sealingmembers are seated.
 5. A resilient roller as claimed in claim 1 in whichthe metal sleeve has a diameter within the range 3 to 10 cm.
 6. Aresilient roller as claimed in claim 1 in which the metal sleeve has athickness within the range 0.03 to 0.3 cm.
 7. A resilient roller asclaimed in claim 1 in which the layer of filling material has athickness within the range 0.01 to 0.35 cm.
 8. A resilient roller asclaimed in claim 1 in which the filling material is a liquid at roomtemperature.
 9. A resilient roller as claimed in claim 8 in which thefilling material is selected from the group consisting of mineral oil,silicone oil, water, glycol and glycerol.